The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the inventors hereof, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
LDPC codes and decoders that are used to decode LDPC codes may be used in numerous applications and devices. For example, data storage, satellite communications, wireless communications, wire-line communications, and power-line communications are applications that may each use LDPC codes and LDPC decoders. Devices such as digital camera flash memory storage, satellites, mobile phones, and other mobile devices may also each use LDPC codes and LDPC decoders.
LDPC codes may be used for correcting errors in information transmitted in noisy communications or a data storage channel. The information may be encoded (by an LDPC encoder) prior to transmission and then subsequently decoded (by a LDPC decoder) when received. The performance capability of an LDPC coding scheme is often described by the code's performance curve. The performance curve is a plot of signal-to-noise ratios (SNRs) vs. Bit Error Rate (BER), or equivalently Sector Error Rate (SER). LDPC codes are one of the best performing error correcting codes, along with Turbo codes, for use in correcting errors in information transmitted on communication and data storage channels.
Traditional LDPC decoders compute decoder extrinsic information by computing a P message for a given variable node of a LDPC code, and then subtract detector extrinsic information from the P message to obtain the decoder extrinsic information. This process may be repeated for some or all of the variable nodes of the LDPC code. Traditional LDPC decoders store the detector extrinsic information in memory, and load the detector extrinsic information at an appropriate time to form the decoder extrinsic information via subtraction.